I'm not the brightest bulb in the chandelier, but several things bother me about this case. First, some people are saying she was trying to break in but if that were the case why would she keep knocking on the door? Most people who are trying to break into a house at night don't want to wake those inside. Even home invaders don't keep banging on the door; instead they attempt to force it open as quickly as possibly to take those inside by surprise. From what I've read at the link OP provided, there is insufficient evidence to establish the woman was trying to break in (banging/knocking on the door is not the equivalent of breaking and entering). According to Michigan's Castle Doctrine it is not enough for the defendant to believe someone is trying to break in. Instead it must also be proved that the person was actually in the process of breaking and entering (the applicable law is shown below).
Second, if the woman was not trying to break in the Castle Doctrine does not apply and the defendant is left with only the standard self-defense provisions that apply in all states: the person must have a reasonable fear of death or serious bodily injury at the time the deadly force is used. I question how anyone could have a reasonable fear of death or serious bodily injury if he is shielded by a closed door and is holding a shotgun. I sure as hell wouldn't be afraid in that situation. This guy actually opened the door and then shot through the screen door and I think this will be his undoing.
Pertinent parts of Michigan law as it applies to the Castle Doctrine (highlights are my own):
(1) Except as provided in subsection (2), it is a rebuttable presumption in a civil or criminal case that an individual who uses deadly force or force other than deadly force under section 2 of the self-defense act has an honest and reasonable belief that imminent death of, sexual assault of, or great bodily harm to himself or herself or another individual will occur if
both of the following apply:
(a)
The individual against whom deadly force or force other than deadly force is used is in the process of breaking and entering a dwelling or business premises or committing home invasion or has broken and entered a dwelling or business premises or committed home invasion and is still present in the dwelling or business premises, or is unlawfully attempting to remove another individual from a dwelling, business premises, or occupied vehicle against his or her will.
(b)
The individual using deadly force or force other than deadly force honestly and reasonably believes that the individual is engaging in conduct described in subdivision (a).
Metro-Detroit Criminal Lawyer: Michigan?s ?Castle Doctrine?
In conclusion, I believe there will be a plea deal; however if it goes to trial the man will be convicted.